Research On Characteristics Of Low Voltage Series Arc Fault

The people's demand of electric power is increasing gradually with the rapid development of electrical technology. According to statistics the proportion of electrical fire frequency had showed an increasing tendency during recent years. The arc fault in electrical lines is one of the main causes of electrical fires, that more than half of what were caused by arc fault. Series arc fault in low-voltage distribution system which is mainly caused by aging of insulation, insulation damaged, circuit shorting and loose contact of wire has the characteristics of randomness, energy concentration, long duration and hard to detected. The traditional circuit breaker for over-current and leakage protection cannot recognize series arc fault accurately to avoid line from electrical fire. The research on arc fault in our country starts relatively late, so that the academic achievements and the products about arc fault are still relatively less. Therefore, the analysis on the characteristics of series arc fault has important significance for protection of people from electrical fires.Firstly, the achievements of research on arc fault at home and abroad has been introduced. And the disadvantages of traditional circuit breaker on prevention of series arc fault was proposed. The most of achievements abroad were speculated that not suitable for prevention of arc fault, which would be probably effected by the type and power of load.Secondly, the series arc fault has been simulated through the series arc fault experiment platform, which was based on the literatures and standards abroad, to get the data of line current under the conditions of normal and fault with different loads. The data was then analyzed by fast fourier transformation through MATLAB and powergui to get the indicators in time domain and frequency domain, which includes time of current pause, average, RMS and rate of rise of current and harmonics of current. The analysis has provided evidence that type and power will influence the characteristics of series arc fault.To solve the problem of effect of type and power of load, the statistics like expected values and fluctuation rates(variances) of indicators in time domain and frequency domain were also made and compared. The reliable statistics of these indicators have been summarized and the detection algorithm which was based onstatistics of current indicators was finally designed. The analysis result of reliable characteristics of series arc fault and related detection algorithm can provide theoretical basis for series arc fault detection.